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Kingdom Plantae
Order Sapindales
Family Anacardiaceae
Species in this genus
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Please enter the plant name in this format: 'Latin name - Common Name'

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Toxicodendron is a genus of flowering plants in the sumac family, Anacardiaceae. It contains woody trees, shrubs and vines, including poison ivy, poison oak, and the lacquer tree. All members of the genus produce the skin-irritating oil urushiol, which can cause a severe allergic reaction. The generic name is derived from the Greek words τοξικος (toxikos), meaning "poison," and δενδρον (dendron), meaning "tree."<ref>Gledhill, D. (2008). The Names of Plants (4 ed.). Cambridge University Press. p. 382. ISBN 9780521866453. </ref>

Members of this genus are sometimes included in the genus Rhus, although recent molecular evidence points to keeping Toxicodendron as a separate monophyletic genus.<ref>Pell, Susan Katherine (18 February 2004). "Molecular Systematics of the Cashew Family (Anacardiaceae) (PhD dissertation at Louisiana State University)". , page 89</ref>

They have pinnately compound, alternate leaves and whitish or grayish drupes. The best known members of the genus in North America are poison ivy, practically ubiquitous throughout most of eastern North America, and poison oak, similarly ubiquitous throughout much of the western part of the continent.

The plants are quite variable in appearance. The leaves may have smooth, toothed or lobed edges, and all three types of leaf edge may be present in a single plant. The plants grow as creeping vines, climbing vines, shrubs, or, in the case of Lacquer Tree and Poison Sumac, as trees. While leaves of poison ivy and poison oaks usually have three leaflets, sometimes there are five or, occasionally, even seven leaflets. Leaves of Poison Sumac have 7–13 leaflets, and of Lacquer Tree, 7–19 leaflets.

The common names come from similar appearances to other species that are not closely related and to the allergic response to the urushiol. Poison oak is not an oak (Quercus, family Fagaceae), but this common name comes from the leaves' resemblance to white oak (Quercus alba) leaves, while Poison ivy is not an ivy (Hedera, family Araliaceae), but has a superficially similar growth form. Technically, the plants do not contain a poison; they contain a potent allergen.

The resins of certain species native to Japan, China and other Asian countries, such as T. vernicifluum (Lacquer Tree) and T. succedaneum (Wax Tree), are used to make lacquer, and, as a byproduct of lacquer manufacture, their berries are used to make japan wax.

Avoidance, treatment, and safety

For specific information on prevention and treatment of Toxicodendron rashes, see Urushiol-induced contact dermatitis.

Selected species of Toxicodendron


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